According to portable terminals such as mobile phones which can be operated by using a touchpad, based on a value indicating a degree of contact made to the touchpad (value indicating an electrostatic capacitance, for example), a contact area on the touchpad to which the contact has been made is detected, and processing allocated to the contacted area is performed.
Accordingly, in the case where, for example, a user's body part besides his/her finger or the like contacts the touchpad (referred to hereinafter as “erroneous contact”), processing that user does not intend is performed (referred to hereinafter as an “erroneous operation”).
In response to this problem, Patent Literature 1 discloses a control method, for example. According to this control method, it is judged as to whether the size of a contact area on a touchpad to which contact has been made exceeds a predetermined size value. When the size of the contacted area exceeds the predetermined size value, control is performed such that processing based on this contact is not performed.
Here, in the case where the method disclosed in the Patent Literature 1 is used, it can be assumed that an area on the touchpad, which has a value indicating a degree of contact made to the touchpad (value indicating an electrostatic capacitance, for example) that exceeds a predetermined threshold, is determined as a contacted area on the touchpad, and judgment is performed as to whether the determined contacted area exceeds the predetermined size value.
Accordingly, as the predetermined size value, a boundary value of area size is determined, which is the boundary between values in the case of contact made by the user's finger or the like and values in the case of contact made by the user's body part beside the finger or the like. As a result, in the case where contact is made to the touchpad by the user's body part beside his/her finger or the like, it is possible to prevent the occurrence of erroneous operations.